TOPCon battery and preparation method and assembly thereof

Abstract

The invention relates to the technical field of solar cells, and provides a TOPCon cell and a preparation method and assembly thereof. The TOPCon battery comprises a silicon substrate, and a first passivation layer, a second passivation layer and a third passivation layer which are sequentially arranged on the back surface of the silicon substrate, the first passivation layer is made of silicon oxide, the second passivation layer is a doped silicon layer, and the third passivation layer comprises the following raw materials in parts by weight: 3-5 parts of a polyvinyl benzene compound and 90-100 parts of a solvent. According to the technical scheme, the problem of low photoelectric conversion efficiency of the TOPCon battery in the related technology is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a TOPCon cell and a preparation method and assembly thereof. Background Art

[0002] TOPCon cells are tunnel oxide passivated contact solar cells with N-type silicon as the substrate. In the field of new energy, TOPCon cells can convert solar energy into electrical energy to provide power support for various devices and systems. In photovoltaic power stations, a large number of TOPCon cell modules can form photovoltaic arrays, convert sunlight into direct current, and then convert it into alternating current through inverters and then connect it to the power grid, providing clean electric energy for society. However, the current TOPCon cells still have shortcomings in terms of photoelectric conversion efficiency. The low photoelectric conversion efficiency of TOPCon cells will not only reduce the discharge power, but also increase the cost of photovoltaic power generation. Therefore, it is very necessary to develop a TOPCon cell with high photoelectric conversion efficiency. Summary of the invention

[0003] The present invention provides a TOPCon cell and a preparation method and assembly thereof, which solve the problem of low photoelectric conversion efficiency of the TOPCon cell in the related art.

[0004] The technical solution of the present invention is as follows: The present invention proposes a TOPCon battery and a first passivation layer, a second passivation layer and a third passivation layer sequentially arranged on the back side of the silicon substrate, the material of the first passivation layer is silicon oxide, the second passivation layer is a doped silicon layer, and the third passivation layer includes the following component raw materials in parts by weight: 3 to 5 parts of polyvinylbenzene compound and 90 to 100 parts of solvent.

[0005] As a further technical solution, the material of the silicon base is an N-type silicon substrate.

[0006] As a further technical solution, the thickness of the first passivation layer is 1-2 nm.

[0007] As a further technical solution, the thickness of the second passivation layer is 50-70 nm.

[0008] As a further technical solution, the thickness of the third passivation layer is 30-50 nm.

[0009] As a further technical solution, the polyvinylbenzene compound includes one or both of poly(4-vinylbiphenyl) and poly(α-methylstyrene).

[0010] As a further technical solution, the solvent includes one or more of methanol, ethanol, and isopropanol.

[0011] As a further technical solution, the raw materials of the third passivation layer also include: 1 to 2 parts of dispersant.

[0012] As a further technical solution, the dispersant includes sodium dodecylbenzene sulfonate.

[0013] In the present invention, sodium dodecylbenzene sulfonate is added as a dispersant to reduce the surface tension between the polyvinylbenzene compound particles, making it easier to disperse in the solvent, thereby ensuring the uniformity of the mixing of the third passivation layer raw materials and further improving the photoelectric conversion efficiency of the TOPCon cell.

[0014] As a further technical solution, the dispersant further comprises a phenylsilanol compound, and the mass ratio of the sodium dodecylbenzene sulfonate to the phenylsilanol compound is 5:1-2.

[0015] In the present invention, sodium dodecylbenzene sulfonate and phenylsilanol compounds are added as dispersants at the same time, and the mass ratio of the two is coordinated to exert the synergistic effect of the two, thereby ensuring the uniformity and consistency of the passivation layer and further improving the photoelectric conversion efficiency of the TOPCon cell.

[0016] As a further technical solution, the phenylsilanol compound includes one or more of methyldiphenylsilanol, 1,1,3,3-tetraphenyl-1,3-disiloxanediol, and (4-methoxyphenyl)dimethylsilanol.

[0017] As a further technical solution, the phenylsilanol compound is methyldiphenylsilanol.

[0018] The present invention also provides a method for preparing a TOPCon battery, comprising the following steps: S1, after the silicon substrate is roughly polished, deposition is performed in an oxygen atmosphere to form a first passivation layer; S2, depositing on the surface of the first passivation layer under the doping gas to form a second passivation layer; S3, mixing the raw materials of the third passivation layer, coating the raw materials on the surface of the second passivation layer, and curing to form a third passivation layer to obtain a battery cell, forming metal electrodes on the front and back sides of the battery cell, and sintering to obtain a TOPCon battery.

[0019] As a further technical solution, the deposition method in S1 is chemical deposition, and the deposition temperature is 500-650°C.

[0020] As a further technical solution, the deposition method in S2 is chemical deposition, the deposition temperature is 500-650° C., the doping gas is composed of silane and phosphine, the silane flow rate is 50-80 SCCM, and the phosphine flow rate is 5-10 SCCM.

[0021] As a further technical solution, the coating includes one or more of spray coating, scraper coating and spin coating.

[0022] As a further technical solution, the curing temperature in S3 is 80-100° C., and the curing time is 60-90 min.

[0023] As a further technical solution, the materials of the front and back metal electrodes of the battery cell in S3 are both silver paste, and the front and back metal electrodes are formed by screen printing. The thickness of the front metal electrode is 20μm, and the thickness of the back metal electrode is 15μm.

[0024] As a further technical solution, the sintering temperature in S3 is 700-900° C., and the sintering time is 20-30 seconds.

[0025] The present invention also provides a TOPCon battery assembly, comprising the TOPCon battery or the TOPCon battery prepared by the preparation method of the TOPCon battery, a bus bar, a conductive film, and a packaging material.

[0026] The working principle and beneficial effects of the present invention are: In the present invention, the silicon substrate serves as a basic support and provides a stable platform for the construction of the entire battery. Its good semiconductor properties ensure the basis for the generation and transmission of carriers. Silicon oxide is used as the first passivation layer and a doped silicon thin layer is used as the second passivation layer, which effectively reduces the number of dangling bonds on the surface of the silicon substrate and reduces the surface recombination rate, so that more generated carriers can participate in the electrical process of the battery. The third passivation layer uses polyvinylbenzene compounds and solvents as raw materials to further reduce the surface recombination rate, improve the stability and reliability of the battery, and improve the photoelectric conversion efficiency of the TOPCon battery. DETAILED DESCRIPTION

[0027] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] In the following examples and comparative examples: Silicon substrate: N-type silicon substrate; First passivation layer: thickness is 2nm; Second passivation layer: thickness 60nm; The third passivation layer: thickness is 40nm; Poly(4-vinylbiphenyl): weight average molecular weight is 115,000; Poly(α-methylstyrene): weight average molecular weight 300,000; Polystyrene: weight average molecular weight is 280,000; Silver paste: model is PERC, purchased from Suzhou Jingyin New Material Technology Co., Ltd.

[0029] Example 1 A method for preparing a TOPCon battery comprises the following steps: S1. After the silicon substrate is roughly polished, the silicon substrate is placed in a high-temperature furnace by a chemical deposition method. In a dry oxygen environment, the temperature is controlled to be 500° C., and a first passivation layer is deposited on the back of the silicon substrate; S2, using low pressure chemical deposition method, using silane and phosphine as source gases to pass into the reaction chamber of the reactor, controlling the silane flow rate to 50 SCCM, the phosphine flow rate to 5 SCCM, and after deposition at 500° C., depositing the second passivation layer on the surface of the first passivation layer; S3. Weigh 3 parts of poly(4-vinyl biphenyl) and 90 parts of methanol, mix well, spray them on the surface of the second passivation layer, and cure them at 80°C for 90 minutes to obtain a battery cell. Apply silver paste on the front and back of the battery cell by screen printing, and sinter at 700°C for 30 seconds to form metal electrodes. The thickness of the front metal electrode is 20μm, and the thickness of the back metal electrode is 15μm, thus obtaining a TOPCon battery.

[0030] Example 2 A method for preparing a TOPCon battery comprises the following steps: S1. After the silicon substrate is roughly polished, a low-pressure chemical deposition method is used to place the silicon substrate in a high-temperature furnace, and the temperature is controlled to 600° C. in a dry oxygen environment to deposit a first passivation layer on the back of the silicon substrate; S2, using low pressure chemical deposition method, using silane and phosphine as source gases to pass into the reaction chamber of the reactor, controlling the silane flow rate to 65 SCCM, the phosphine flow rate to 8 SCCM, and after deposition at 600° C., depositing the second passivation layer on the surface of the first passivation layer; S3. Weigh 4 parts of poly(4-vinyl biphenyl) and 95 parts of ethanol, mix well, apply them on the surface of the second passivation layer, and cure them at 90°C for 75 minutes to obtain a battery cell. Apply silver paste on the front and back of the battery cell by screen printing, and sinter at 800°C for 25 seconds to form metal electrodes. The thickness of the front metal electrode is 20μm, and the thickness of the back metal electrode is 15μm, thus obtaining a TOPCon battery.

[0031] Example 3 A method for preparing a TOPCon battery comprises the following steps: S1. After the silicon substrate is roughly polished, a low-pressure chemical deposition method is used to place the silicon substrate in a high-temperature furnace, and the temperature is controlled to be 650° C. in a dry oxygen environment to deposit a first passivation layer on the surface of the silicon substrate; S2, using low pressure chemical deposition method, using silane and phosphine as source gases to pass into the reaction chamber of the reactor, controlling the silane flow rate to 80 SCCM, the phosphine flow rate to 10 SCCM, and after deposition at 650° C., depositing the second passivation layer on the surface of the first passivation layer; S3. Weigh 5 parts of poly(α-methylstyrene) and 100 parts of isopropanol, mix well, spin-coat on the surface of the second passivation layer, and cure at 100°C for 60 minutes to obtain a battery cell. Apply silver paste on the front and back of the battery cell by screen printing, and sinter at 900°C for 20 seconds to form metal electrodes. The thickness of the front metal electrode is 20μm, and the thickness of the back metal electrode is 15μm, thus obtaining a TOPCon battery.

[0032] Example 4 A method for preparing a TOPCon battery comprises the following steps: S1. After the silicon substrate is roughly polished, a low-pressure chemical deposition method is used to place the silicon substrate in a high-temperature furnace, and the temperature is controlled to 500° C. in a dry oxygen environment to deposit a first passivation layer on the back of the silicon substrate; S2, using low pressure chemical deposition method, using silane and phosphine as source gases to pass into the reaction chamber of the reactor, controlling the silane flow rate to 50 SCCM, the phosphine flow rate to 5 SCCM, and after deposition at 500° C., depositing the second passivation layer on the surface of the first passivation layer; S3. Weigh 3 parts of poly (4-vinyl biphenyl), 90 parts of methanol, and 1 part of sodium dodecylbenzene sulfonate, mix well, spray on the surface of the second passivation layer, and cure at 80°C for 90 minutes to obtain a battery cell. Apply silver paste on the front and back of the battery cell by screen printing, and sinter at 700°C for 30 seconds to form metal electrodes. The thickness of the front metal electrode is 20μm, and the thickness of the back metal electrode is 15μm, thus obtaining a TOPCon battery.

[0033] Example 5 Compared with Example 4, the difference in Example 5 is that the added amount of sodium dodecylbenzene sulfonate is 2 parts.

[0034] Example 6 Compared with Example 5, the difference of Example 6 is that sodium dodecylbenzenesulfonate is replaced by an equal amount of (4-methoxyphenyl)dimethylsilanol.

[0035] Example 7 Compared with Example 5, the difference of Example 7 is that sodium dodecylbenzene sulfonate is replaced by sodium dodecylbenzene sulfonate and (4-methoxyphenyl)dimethylsilanol in a mass ratio of 5:1.

[0036] Example 8 Compared with Example 5, the difference of Example 8 is that sodium dodecylbenzene sulfonate is replaced by sodium dodecylbenzene sulfonate and (4-methoxyphenyl)dimethylsilanol in a mass ratio of 5:2.

[0037] Example 9 Compared with Example 8, Example 9 is different in that (4-methoxyphenyl)dimethylsilanol is replaced by an equal amount of methyldiphenylsilanol.

[0038] Example 10 Compared with Example 8, Example 10 is different in that (4-methoxyphenyl)dimethylsilanol is replaced by an equal amount of 1,1,3,3-tetraphenyl-1,3-disiloxanediol.

[0039] Comparative Example 1 Compared with Example 1, Comparative Example 1 is different in that the third passivation layer is removed.

[0040] Comparative Example 2 Compared with Example 1, Comparative Example 2 is different in that poly(4-vinylbiphenyl) is replaced by an equal amount of polystyrene.

[0041] The TOPCon batteries prepared in Examples 1 to 10 and Comparative Examples 1 to 2 were tested: The test results are shown in the following table: Table 1 Performance test results of TOPCon batteries prepared in Examples 1 to 10 and Comparative Examples 1 to 2

[0042] Compared with Comparative Examples 1 and 2, Example 1 adds poly(4-vinyl biphenyl) as the third passivation layer. As a result, the conversion efficiency and fill factor of Example 1 are higher than those of Comparative Examples 1 and 2, indicating that when poly(4-vinyl biphenyl) is added as the third passivation layer, the photoelectric conversion efficiency of the TOPCon cell can be improved.

[0043] Compared with Example 1, Examples 4 and 5 added sodium dodecylbenzene sulfonate as a dispersant. As a result, the conversion efficiency and fill factor of Examples 4 and 5 were higher than those of Example 1, indicating that when sodium dodecylbenzene sulfonate was added as a dispersant, the photoelectric conversion efficiency of the TOPCon cell could be further improved.

[0044] Compared with Examples 5 and 6, Examples 7 to 10 simultaneously added sodium dodecylbenzene sulfonate and phenylsilanol compounds as dispersants. As a result, the conversion efficiency and filling factor of Examples 7 to 10 were higher than those of Examples 5 and 6, indicating that sodium dodecylbenzene sulfonate and phenylsilanol compounds played a synergistic role and could further improve the photoelectric conversion efficiency of the TOPCon cell.

[0045] In Examples 8 to 10, different types of phenylsilanol compounds were added, and the conversion efficiency and fill factor of Example 9 were higher than those of Examples 8 and 10, indicating that when the added phenylsilanol compound was methyldiphenylsilanol, the photoelectric conversion efficiency of the obtained TOPCon cell was higher.

[0046] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A TOPCon battery, characterized in that: The invention comprises a silicon substrate and a first passivation layer, a second passivation layer and a third passivation layer which are sequentially arranged on the back side of the silicon substrate, wherein the material of the first passivation layer is silicon oxide, the second passivation layer is a doped silicon layer, and the third passivation layer comprises the following component raw materials in parts by weight: 3 to 5 parts of a polyvinylbenzene compound and 90 to 100 parts of a solvent.

2. A TOPCon battery according to claim 1, characterized in that: The polyvinylbenzene compound includes one or both of poly(4-vinylbiphenyl) and poly(α-methylstyrene).

3. A TOPCon battery according to claim 1, characterized in that: The solvent includes one or more of methanol, ethanol and isopropanol.

4. A TOPCon battery according to claim 1, characterized in that: The raw materials of the third passivation layer also include: 1-2 parts of dispersant.

5. A TOPCon battery according to claim 4, characterized in that: The dispersant includes sodium dodecylbenzene sulfonate.

6. A TOPCon battery according to claim 5, characterized in that: The dispersant further comprises a phenylsilanol compound, and the mass ratio of the sodium dodecylbenzene sulfonate to the phenylsilanol compound is 5:1-2.

7. A TOPCon battery according to claim 6, characterized in that: The phenylsilanol compound includes one or more of methyldiphenylsilanol, 1,1,3,3-tetraphenyl-1,3-disiloxanediol, and (4-methoxyphenyl)dimethylsilanol.

8. A TOPCon battery according to claim 7, characterized in that: The phenylsilanol compound is methyldiphenylsilanol.

9. A method for preparing a TOPCon battery according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1, after the silicon substrate is roughly polished, deposition is performed in an oxygen atmosphere to form a first passivation layer; S2, depositing on the surface of the first passivation layer under the doping gas to form a second passivation layer; S3, mixing the raw materials of the third passivation layer, coating the raw materials on the surface of the second passivation layer, and curing to form a third passivation layer to obtain a battery cell, forming metal electrodes on the front and back sides of the battery cell, and sintering to obtain a TOPCon battery.

10. A TOPCon battery assembly, comprising the TOPCon battery according to any one of claims 1 to 8 or a TOPCon battery prepared by the method for preparing a TOPCon battery according to claim 9, a bus bar, a conductive film, and a packaging material.

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